Dynamo-electric machine



c. J. FECHHEIMER DYNAMO-ELECTRIC MACHINE Filed Nov. '1, 1937 2 Sheets-sheet 2 Jan. 2,` .1940.

Patented Jan. 2, 1940 mimmo-nascosto Ms Carl il. Fechlieimer, Milwaukee, wie., or to 'The lllonis Allis Company, Milwaukee, Wint. n

corporation of' Wisconsin Application November li, 193'?, Seriali No. l'iJiSS v 6 Claims. (Qi. lil-252i This invention relates to dynamo-electric ma complete example of the physical embodiment oi' chines and refers particularly to so-called fan the invention constructed in accordance with the cooled direct current motors. best mode so far devised for the practical applin dynamo-electric machines of this type, espe cation of the principles thereof, and in which:

w cially in the larger sizes, dimculty has been ex'- Flgure l is a longitudinal sectional view 5 perienced in properly ventilating the armature. through a direct current electric motor embody- Heretofore, the construction of these machines ing this invention; and has been such that the pressure generated by the Figure 2 is a cross sectional view taken through centrifugal force of the rotating armature was Figure 1 on the plane of the line 2 2.

.opposed to the pressure produced by the fan and Referring now particularly to the accompanylo as a consequence, the air in juxtaposition to the ing drawings in which like numerals indicate like rotor was more or less stagnant, making it dimparts, the numeral 5 designates the housing oi cult to carry oil the heat generated thereat. As the motor, which in the present embodiment cona result of this condition the armature tempera'- sists of a cylindrical part generally referred to 35 ture rise was either too great or the machine was as the frame, and end walls 1 and l joined thereu larger than it should have been for a particular to with an explosion-proof connection. The end rating. A n walls 1 and 8 carry bearings 9 in whichthe shaft This invention therefore has as one of its pri- I0 ofthe rotor is journalled. Like the connecmary objects to improve the construction of dytions between the end walls and the frame the im name-electric machines of this type so that the joint between the end walls and the shaft is long zo armature will be properly ventilated by an ade- 'enough to guard vagainst the possibility of ignited quate passage of cooling air therethrough. gases passing out from the interior of the Another object of this invention is to provide a. houslndynamo-electric machine having a rotor core pro- The frame 5 has alternate lnsitudmel externe1 vided with air vents through which air flows at and internal air passages er 'channels Il end l2. 25

relatively high velocity to carry off the heat genrespectively. The external eil Passages are Open erated thereat. l l at both ends to the atmosphere andthe internal Another object of this invention is to provide a passages l! open to the interior of the housing simple manner of forming these air ventsand of or casing at both ends. conducting air thereto. l Radial ribs I3 on the outer surface of the end 30 Another object of this invention is to provide Wall 1 increase heat conduction to the outside baille means'so situated with respect to the rotor atmosphere end t0 further facilitate the dissipef core and the fan that the air issuing from the tion of heat from the end wall 1, a peripheral fan is divided into two-circuits or paths, one of hood I4 guides and directs air issuing from the which extends longitudinally along thel frame to adjacent ends 0f the external eir messages ll 315` the opposite end of the machine, and the other inwardly over the ribbed face of the end wall. of which extends inwardly over one end wall to Engaging the opposite end of the frame and the central air passage of the rotor. spaced from the adjacent end wall 8 is a cover Still another object of this invention is to proplate t6 having a central grilled inlet opening vide a manner of Ventilating the interior of a` I8. Air admitted through the opening IB passes o totally enclosed dynamo-electric machine where. directly to a fan l1 fixed to `the adjacent end by two definite air circuits are established so reof the rotor shaft, which fan throws the air out lated that the centrifugal force of the rotor has into the longitudinal air passages Il. a cumulative effect on the fan which initially pro- Carried by the inner wallof the frame 8 nearer \duces the desired air motion. the end wall 1 than the wall 8 are stator poles Il With the above and other objects in view which provided with the usuel 0011s I9 end Ilmllirls will appear as the description proceeds, thisinwithin these poles is a laminated rotor core 20. vention resides in the novel construction," combi- The rotor core v2li is mounted from the shaft I0 nation and arrangement of parts substantially as by means of longitudinal equi-spaced bars Il 50 hereinafter described, and more particularly dewhich are carried by the shaft. The core is fixed 50 I nned by theappended claims. it being understood to these bars and is assembled between shoulders that such changes in the precise embodiment of 22 at onecnd thereof and keys 23 secured in the the hereindisclosed invention may be made as opposite ends thereof.

come within the scope of the claims. The core is divided into endwise .spaced seo-k 5g The accompanying drawings illustrate one l tions with the spaces therebetween providing 5 transverse `or radial air passages or vents 24 leading from the space within the laminated core proper, to the outer 'periphery of the core. Disposed within these transverse or radial spaces are blades 25 which serve to hold the core sections properly spaced 4and also form fans to throw air outwardly from the central passage to the out-er periphery of the core.

As shown in Figure 2, the blades 25 have their outer portions which lie between the coils 26 of the rotor radial and their inner portions directed to one side so as to be tangential to a circle slightly larger than the diameter of the adjacent portion of the shaft. These inner portions of the blades are fixed to at rings 21 vto hold the same assembled in one unitary structure.

Between the rotor core and the end wall l the shaft carries a commutator 28 with which brushes (nottshown) cooperate.

Between the rotor core and the end wall 1 is a fan 30. The fan is mounted on-the inner face of a dat circular baille plate 3| extending outwardly from a cylindrical lbaille 32 iixed to a supporting spider 33 which in turn is mounted directly on the shaft. The cylindrical baille 32 lies just inside the rotor coils and has openings 32 in line with the coils, and the iiat baille 3| is located directly adjacent to the ends of the rotor coils. Fastened to the fan blades is a baille ring 34 which carries a cylindrical flange 35 arranged in close juxtaposition to one edge of the adjacent inlet `openings of the longitudinal air passages l2.

The opposite end of the rotor also has a cylinvdricalbaiile 36 mounted inside the rotor coils 26 with the outer end thereof lying close to the commutator and its inner portion provided with .air openings 31 to allow air owing out along the rotor shaft to pass radially out through and around the adjacent ends of the coils 26.

Fixed to the end wall 'I is a stationary flat bafe vplate 38 provided with a baille ring 33 at its inner periphery. The baille plate 38 is spaced from the inner face of the end wall 'I and coop-` erates therewith to provide an air passage for leading part of the air which issues from the fan 30 inwardly across the inner face of the wall 1 to the center of the rotor.

In operation the air issuing from the ian 30 is divided into two streams. The main stream which takes approximately sixty-five per cent of the air, flows through the longitudinal channels l2 where it is cooled by the flow of external air in adjacent passages Il. 'I'he other stream which takes the remaining part of the air issuing from the fan 30', iiows radially inward between the baiile plate 38 and the end wall 1, to the rotor shaft, being cooled in its passage by contact with the end wall.

The centrifugal action of the rotor throws this air outwardly through the rotor core to join the main stream which has been cooled by its passage through the longitudinal ducts i 2 and has swept across the commutator and around the stator poles.

`With this distribution of the Ventilating air, the pressure generated by the`fan 30.1s added to the pressure produced by centrifugal force in the armature vents. Consequently, the two impelllng forces are cumulative so that the air flowing through the vents in the armature core has a highvelocity and rapidly carries on the heat generated-at the rotor or armature.

From thev foregoing description taken'in connection with the accompanying drawings, it will be readily apparent to those skilled in the art,

that this invention provides a substantial 1mprovement in the means for cooling and ventilating fan cooled totally enclosed dynamo electric machines, and it is to be understood that while the embodiment of the invention illustrated is a direct current motor having a commutator the invention is also equally applicable to alternating current commutator motors and to the slip ring rotor type of induction motor, for in such instances the slip rings merely occupy the location of the commutator in a D. C. machine.

What I claim as my invention is:

1. In a dynamo-electric machine: a frame having alternate internal and external longitudinal air passages opening respectively at their ends to the inside of the frame and to the outside atmosphere; end walls closing the end of the frame to form a closed casing; bearings carried by the end walls; a rotor journalled in said bearings. said rotor having a laminated core provided with radial vents, and a central longitudinal air passage leading to the radial vents from the ends of the core; a fan within the casing arranged tu throw air into the internal longitudinal passages of the frame; and baille means arranged in juxtaposition to the fan for guiding part of the air issuing from the fan inwardly over one end wall to the central air passage in the rotor core and its radial vents.

2. In a dynamo-electric machine: a closed substantially cylindrical casing aving alternately external and internal longitu inal air passages in its cylindrical wall opening respectively a'nd at both ends tothe outside atmosphere and to the interior of the casing; bearings carried by the end walls of the casing; a rotor journalled in said bearings and having a central longitudinal air passage through its core, and radial air passages leading therefrom; a fan carried by the rotor and positioned adjacent to one end wall and substantially in line with the adjacent open4 ends of the internal longitudinal air passages in the casing wall for driving air into said longitudinal passages, which air iiows therethrough to return to the casing interior at the opposite end of the machine; and baille means between the fan and said end wall for conducting part of the air issuing from the fan inwardly to the central longitudinal air passage and thence to the radial passages through the core.

3. In a dynamo-electric-machine: a substantially cylindrical frame having spaced alternate external and internal longitudinal air passages through its outer wall opening respectively and at both ends to the outside atmosphere and to theinterlor of the casing; means for causing a flow of air through the external air passages; bearings carried by the end walls of the casing;

ya rotor journalled in said bearings and having a laminated core provided with a central longitudinal air passage and radial air passages leading outwardly through the core from said centralpassage; a commutator carried by the rotor near one end wall ofV theA casing; a fan carried by the rotor near the opposite end wall of the casing and arranged to throw air outwardly 4into the adjacent open ends of the internal longitudinal air passages of the frame which air travels therethrough to return to the interiorof the casing adjacent the commutator; and a baille carried by the end wall adjacent to the fan to guide part of the air issuing from the fan inwardly to the central longitudinal air passage ot therotor so that such air can flow out through the radial passages of the rotor to join the air iiowing over the commutator in its return to the fan.

4. In a dynamo-electric machine of the enclosed fan-cooled direct current, type: a frame having adjacent external and internal longitudinal air passages opening respectively and at both ends to the outside v interior of the frame; end walls closing the ends of the frame; bearings carried by the end walls; a rotor having its shaft journalled in said bearings and having a laminated core and a commutator; stator polesk carried by the frame in cooperative relation to the rotor core, said rotor core having a central air passage therethrough and having radial air passages leading from its central passage to the periphery of the rotor so that air enteringthe central air passage is thrown outwardly through said radial passages; a fan carried by the rotor adjacent one end wall and in line withthe adjacent open ends of the internal longitudinal air passages through the casing wall to cause air to enter the same and travel therethrough toward the opposite end of the machine where it sweeps across thecommutator -and returns past the stator poles to the fan; baille means to guide part of the air issuing from the fan inwardly across the adjacent end wall to the central longitudinal air passage for admission to the radial air passages of the rotor core; Aand means for driving air through the external longitudinal air passages of the frame.

5. In a dynamo-electric machine: a frame having alternate internal and external longitudinal,

air passages opening respectively at their ends to the inside of the frame and to the outside atmosphere; end walls closing the endspof the frame to form a closed casing; bearings carried by the end walls; a rotor journalled in said bearings, said rotor having a`laminated core provided with radial vents, and a central longitudinal air passage leading to the radial vents from the ends of the core; a rotatable baille within the casing adjacent to one end wall and atmosphere and to the- Y' internal longitudinal in spaced relationship therewith to delinea radial air passage and having another part angular thereto and extending toward the rotor core and spaced from the rotor shaft to define a longitudinal air passage from said radial passage to the central longitudinal air passage of the rotor core; impellers carried by the rotatable baille and arranged to throw air outwardly into the adjacent open ends of the internal 1ongitudinal air passages in the frame; said rotatable baiiie being so disposed with respect to the air passage openings as to guide part of the air issuing from the impellers inwardly through said radial passage to be conducted to the central air passage in the rotor core and its radial vents by the angular portion of the baille.

d. In a dynamo-electric machine: a frame having alternate internal and external longitudinal air passages opening respectively at their ends to the inside of the frame and to the outside atmosphere; end walls closing the ends of the l frame to form a closed casing; bearings carried by the end walls; a rotor journalled in said bearings, said rotor having a laminated core provided with radial vents. and a central longitudinal air from the ends of the core; stationaryand rotatable bafes adjacent one end' of the casing; said stationary baille being carried by said end wall in spaced relationship therewith and extending radially outwardly to a point adjacent to the mouths of the internal longitudinal air passages, said baffles cooperating to form a radial air passage leading to the mouths of the internal longitudinal air passage, impellers carried by the rotatable baffle for circulating air through said internal longitudinal air passages of the frame and radially inwardly through the space between the stationary baille and said end wall; and

passage leading to .the radial vents 4' means on said rotatable baille for directing air I flowing through the space between the stationary baille and said end wall to the central air passage in the rotor core and its radial vents.

CARL J. FECHHEIMER. 

